1. Field of the Invention
This invention generally relates to needle guards for syringes and more particularly to guards that protect attendants from being stuck inadvertently by a hypodermic needle attached to a syringe.
2. Description of Related Art
Medical personnel run a substantial risk of disease transmittal if they are inadvertently stuck by a hypodermic needle after its use. The proliferation of AIDS, hepatitis and related infectious diseases transferred by hypodermic needles has led to the development of various articles for protecting healthcare workers from being stuck inadvertently. Many of these articles include guards or covers for the needle; some attach to the syringe.
U.S. Pat. No. 2,854,976 to Heydrich discloses a protective device for needles of hypodermic syringes. This device has a structure at one end for engaging the proximal end of a syringe needle and a structure for encasing the point of the needle at the distal end. In one embodiment a structure can be disposed intermediate the ends to engage and support the needle. In all embodiments, spaced upper parts of an H-shaped structure engage the syringe needle; diametrically opposed and extending wings of that structure provide a finger grip. An attendant's fingers are brought into proximity to the needle, although not the end of the needle. Moreover, it appears that an attendant must use two hands to hold that syringe and simultaneously operate the H-shaped structure to remove the protective device from the syringe.
U.S. Pat. No. 4,946,447 to Hardcastle et al. discloses a protective cover or sleeve for a hypodermic needle. This protective sleeve includes a formed resilient plastic body split longitudinally to form slightly greater than a semicylinder. The body is snapped onto the barrel of a hypodermic needle before or after the needle is used. It may be slid longitudinally over the needle to protect against accidental puncture by the needle after the needle is used and locks into this position. In order to protect an attendant, the protective cover must be attached to the syringe prior to and during its use.
U.S. Pat. No. 4,985,020 to Kasuya discloses a guard with a finger grip that facilitates the positioning of the guard over a needle. When the guard is positioned properly, a proximate end engages a hub and locks the guard in place. However, a finger grip adjacent the proximal end brings the attendant's fingers into close proximity with the needle.
U.S. Pat. No. 5,026,356 to Smith discloses an open sleeve that attaches to a syringe body and that carries an axially movable L-shaped member and rocker spring. When the L-shaped member moves axially to a distal position, at the tip of the hypodermic needle, the L-shaped member deflects and covers the needle tip under the influence of the rocker spring. At other positions the L-shaped member rests against the side of the needle. This structure does not cover the needle completely so an attendant can still contact portions of the needle. The open sleeve and L-shaped member remains on the needle during use and operation requires two hands.
U.S. Pat. No. 5,092,461 to Adam discloses a needle cover that is adapted for one-handed operation. It has a tip portion for positive engagement with a needle tip to hold the cover in place over a tip end portion of the needle. The needle cover is essentially smooth and has no finger grips for an attendant. In use the guide slides forward or toward the distal end of the needle to release the needle. It slides rearwardly or proximally to cover the needle. The device apparently remains in place on the syringe during use.
U.S. Pat. No. 5,087,249 to Deal discloses a tubular guard that slides over the end of a hypodermic needle to engage a hub on the syringe at the proximal end of the needle. An elongated handle terminates with an angularly disposed head member. The head member includes a cavity for receiving and releasably engaging the syringe cap. A pair of opposed resilient clips, or alternatively, a pair of spaced apart walls interconnected at one end form the cavity. This structure does remove an attendant's hands from proximity to the needle. However, an attendant must use both hands simultaneously to grip the syringe and operate the handle.
The following patents disclose covers in which an axial body attaches to a syringe barrel or to a needle hub at the end of the barrel:
U.S. Pat. No. 2,745,403 to Goldberg discloses a disposable cartridge suitable for containing single dosages of medicaments and the like. The cartridge comprises an elongate, tubular body portion of substantially uniform bore, thickened and partially constricted near one end. An annular groove, formed on the outer surface of the tubular body, can engage a closure collar element. An imperforate disc, adapted to being easily pierced by a hypodermic needle and formed of resilient, liquid impervious material, substantially inert toward and insoluble in liquids, solvents and medicaments commonly administered by injection is positioned normal to the axis of said tubular body portion and overlying the opening in the partially constricted end thereof. An essentially cylindrical hub element having an axially located opening extending therethrough has a radially extending, annular flange at one end, disposed coaxially relative to the tubular body portion with its flanged end against the outside surface of said disc. Means on the hub element engage with and support a double-pointed hypodermic needle with one end of said needle extending through the hub opening and piercing the disc. A closure collar element around the flanged end of the hub element and engaging with the annular groove formed on the tubular body end, presses the disc therebetween to provide a liquid-tight partial closure at the end of the cartridge. A movable piston, within the tubular body portion embraces the walls thereof to provide a liquid-tight closure at the open end of the tubular body portion.
U.S. Pat. No. 3,076,455 to McConnaughey et al. discloses a holder for hypodermic syringe cartridges. The holder is formed as a channel having an opening along one side thereof through which the cartridge may be snapped into and out of the holder by lateral movement. The width of the opening is less than the maximum width of the cartridge, and the channel is formed of a stiff spring material so that the holder may be distorted momentarily to permit the insertion and removal of the cartridge.
U.S. Pat. No. 4,795,443 to Permenter et al. discloses a device for sealing the tip of a syringe needle. A cap has a shank extending to a mount adapted to be slidably held by a syringe barrel. The cap moves in a spring bias contact along a needle body and beyond its tip whereupon it springs into alignment with the tip. The cap can then be moved in a reverse direction to seal the needle in the cap.
U.S. Pat. No. 4,867,746 to Dufresne discloses a needle shield that can be attached to a syringe hub. The shield is flexible and moves out of the way of the needle point for insertion into the skin. The shield has a one-piece construction and includes an elongated hood-like body that surrounds the needle and includes at one end a blunt front end shield and at the other end a mounting ring for frictionally engaging the hub of the needle of the syringe. An integral lock on the body snaps over the needle for holding the shield body over the contaminated needle.
U.S. Pat. No. 4,994,046 to Wesson et al. discloses an elongated cylindrical body portion with a spoon-shaped shield member. The cylindrical body can be snapped around a syringe barrel. The spoon-shaped member extends from the distal end of the body portion and can deflect transversely from a non-use configuration to a slightly deflected in use configuration to permit the needle to extend beyond the spoon-shaped member. When the body portion of the guard slides to an extended position, the spoon-shaped member returns to its undeflected configuration. A plurality of ribs formed on the inner wall of the spoon-shaped member engage the needle end thereby to seal the end of the needle.
U.S. Pat. No. 5,074,848 to Burt et al. discloses a needle receptacle with a sheath having a cradle portion and attached barrel. The cradle portion is open along its top portion and includes parallel spaced-apart protective flanges. The barrel end is tapered into a needle receiving portion and includes a flared connection between the cradle and the barrel end to serve as a guide for needles as they are inserted into the barrel. A detent structure prevents the needle from turning.
In a medical environment, an attendant wants to keep one hand free during an injection process in order to maintain contact with the patient or perform some related function. Thus, it is desirable that an attendant be able to remove and replace any needle cover with one hand.
The previously described Goldberg, McConnaughey et al., Adam and Dufresne patents disclose guards for one-handed operation. However, none of these references provides any mechanism for completely covering the needle to minimize the transfer of disease from the needle by accidental contact. Moreover, the operation of the Dufresne guard brings an attendant's fingers into close proximity with the needle tip. Guards proposed by Smith, Permenter et al. and Wesson et al. remain on the syringe during use. The addition of this structure can complicate the injection process. The Deal and Burt et al. patents disclose guards that fully cover a needle, but they each require two hands for removing and replacing the cover. The Kasuya patent discloses a cover that might be adapted for operation by one hand. However, placing the cover on the needle brings an attendant's fingers into close proximity to the needle.